this is very tough; i'm sure as soon as i post this, i'll think of 10 other bands that are equally heavy or heavier for that matter.

i will definitely say black sabbath; they've been my favorite band since i was 10 or 11. listening to their first 3 albums at that age was mindnumbing. it's still an experience to listen to it now. if they had the access to some of the greatest, heaviest production that we have these days when they went in the studio, i don't think any stereo systems could handle the awesomeness.

watchmaker is one of the loudest bands i've ever seen live, though that's not exactly in the category of "heavy."

neurosis, on "locust star" to be precise, is one of the heaviest songs ever, in the sense that arrowhead discussed earlier. when the world ends, i expect to hear that song playing throughout the entire globe.